Seal between members which are rotatable relative to each other

Abstract

A seal assembly situated between two relatively rotatable members and axially separating a space of higher pressure from a space of lower pressure, the seal assembly including a fluid reservoir and a seal exposed to said high pressure and axially slidable to urge fluid from the reservoir into a sealing space when leakage occurs therefrom.

What is claimed is: 
     
       1. A seal between an inner member and an enveloping outer member, such as a shaft and an enveloping housing, which are rotatable with respect to each other, the seal containing a viscous medium such as oil or grease which separates a space containing a gas of higher pressure from a space containing a gas of lower pressure, characterized in that the seal comprises a sleeve which is arranged about the inner member and which is immobile with respect to the outer member, the said sleeve having an inner diameter over an intermediate portion of its length which is larger than the outer diameter of the inner member, an annular gap thus being formed which is in open communication, via at least one port through the sleeve, with an annular chamber which is bounded by the outer wall of the sleeve and the inner wall of the outer member, a viscous medium present in the chamber and the gap communicating therewith being separated from the spaces of higher pressure and lower pressure by means of sealing members between the sleeve and the outer member and the inner member, respectively, the sealing member on the side of the annular chamber which faces the space of higher pressure being arranged to be axially slidable in this chamber for the permanent transfer of the higher gas pressure to the viscous medium. 
     
     
       2. In an assembly including a housing with a bore, a shaft extending through said bore and rotatable relative thereto, with an annular space defined between said bore and shaft, and first means for sealing said annular space and for axially separating spaces containing higher pressure and lower pressure fluids respectively, the improvement in combination therewith, wherein said first means comprises a sleeve situated in said annular space and fixedly secured to said housing, said sleeve having (a) an outer surface which defines with said housing bore an outer annular chamber, (b) an inner surface which defines with said shaft an annular gap, and (c) a duct interconnecting said chamber and gap, a viscous medium filling said chamber, gap, and duct, an inner seal situated between said shaft and sleeve's inner surface, said seal having opposite axial ends exposed to said medium in said gap and to said higher pressure fluids respectively, an outer seal situated between said housing bore and said sleeve's outer surface, said outer seal having opposite ends exposed to medium in said chamber and to said higher pressure fluid respectively, said outer seal being axially slidable in said chamber, whereby, upon leakage of said medium out of said gap, said higher pressure fluid will urge said outer seal to slide, thereby urging said medium to flow from said chamber via said duct into said gap for refilling same. 
     
     
       3. Apparatus according to claim 2, wherein said housing bore has a shoulder surface transverse of the bore axis, and wherein said sleeve has a radially extending flange corresponding to and fixedly engaging said shoulder. 
     
     
       4. Apparatus according to claim 2, wherein said viscous medium comprises oil. 
     
     
       5. Apparatus according to claim 2, further comprising a second outer seal between said housing bore and sleeve outer surface, said second outer seal axially spaced from the first outer seal with said chamber between and communicating with said outer seals. 
     
     
       6. Apparatus according to claim 2, further comprising a second inner seal between said shaft and sleeve inner surface, said second inner seal axially spaced from said first inner seal with said gas between and communicating with said inner seals. 
     
     
       7. Apparatus according to claim 2, wherein said chamber comprises an annular recess only in said housing bore, bounded by said sleeve outer surface. 
     
     
       8. Apparatus according to claim 2, wherein said chamber comprises an annular recess only in said sleeve outer surface, bounded by said housing bore. 
     
     
       9. Apparatus according to claim 2, wherein said gap comprises an annular gap only in said shaft, bounded by said sleeve inner surface. 
     
     
       10. Apparatus according to claim 2, wherein said gap comprises an annular recess only in said sleeve inner surface, bounded by said shaft.